In a service delivery environment through public networks centered around the Internet, values of all information are generally collected on a server side rather than a client side.
In other words, each client (terminal device) is basically a mere viewer browsing information on the Internet. Each client issues various information requests to the Internet, which in return may obtain information of such a client. It means that all information is collected on the Internet and it only offers formulaic information unidirectionally. For this reason, it is difficult for manufacturers of client terminal devices to create an added value.
In order to change such a circumstance, the server-client relationship must be reversed by inverting the access direction. That is, for a home network connected to the Internet, an environment must be created in which an access to the home network is initiated from the Internet and a service from the home network to the Internet is provided.
To achieve this, each device connected to a home network must be uniquely identifiable from an internetwork, and intra-home routing and security problems must be solved. One of the technologies to address this issue is the IPv6 (Internet Protocol version 6).
However, taking account of the environment surrounding the current Japanese carriers and Internet service providers, it may require considerable time until IPv6 becomes widely used. For example, the currently used IPv4 needs at least 2 to 3 years for depreciation and IPv6 service is offered on a test basis only.
In order to immediately achieve an IPv6-enabled network, manufacturers must expand their business to ISP level services, which is very costly and unrealistic for most of them. With this broad range of home network environments with their connection mechanisms widely varying depending on the carrier and ISP, there is a need for a mechanism which absorbs all these differences to realize the IPv6 environment by a standardized approach.
One of the prior art literatures related to the above circumstances is Japanese Patent Application 2001-274845 Publication, although it does not deny the novelty and inventive step of an invention according to the present application.
In the conventional IPv4 environment, the following problems arise in order to achieve bidirectional accesses between the home network and the Internet which would be realized by IPv6 networks.
In the current IPv4 environment, for example, when installing a network home appliance at home, it should be connected to a router connected to the Internet through the home network. For this reason, an IP address of the network home appliance becomes a private address and cannot be accessed from non-home network.
Thus an access to the network home appliance has been conventionally achieved by employing a dedicated router capable of controlling the network home appliance, or by first accumulating information for controlling the home network appliance at a data center provided on the Internet and next retrieving the information by performing polling from the network home appliance.
However, when using the dedicated router, the system's versatility decreases and cost increases. When retrieving the control information by polling, accesses cannot be made real time and the network and server load increases.
Considering the above situation, the purpose of the present invention is to provide an Internet connection system capable of bidirectional communications between the home network and the Internet by relatively simple means, enabling manufacturers of client-side network home appliances to find a unique added value.